Gold standard diagnostic criteria for diagnosing acute infection in older adult patients in the Emergency Department do not currently exist. These patients often have atypical presentations which can complicate diagnosis and treatment. The development of an antimicrobial stewardship program for Emergency Department older adult patients can ultimately improve the accuracy of diagnosis and correct antimicrobial prescribing. This research study involves data collection from enrolled subjects and treating physicians. The data will be collected using a patient interview which will be answered directly by the patient or caregiver. Additional surveys will be administered to the Emergency Department treating physician and subsequent physician. Additional data will be abstracted from the Emergency Department chart and from additional charts that often accompanies the patient to the Emergency Department. A physician adjudication process will occur if there is disagreement in diagnosis between the treating Emergency Department physician and succeeding physician.